1. Field of the Invention
The present invention relates to an agent for subjecting fiber material of native cellulose to a pretreatment in alkaline treatment baths and to a process of treating such fiber material as well as to the thus treated fiber material.
2. Description of the Prior Art
Before bleaching, dyeing, printing fibers of native cellulose and fabrics made therefrom, such fibers and especially cotton are usually freed of their natural fatty, collenchymatous, pectin, and lignin substances, the residues of the seed coats, and the usually oily contaminations due to the spinning and weaving process. Such accompanying substances interfere with the above mentioned finishing processes.
Heretofore, such contaminations and impurities were eliminated by a treatment with alkaline agents such as with sodium carbonate and/or sodium hydroxide solutions whereby the fiber material was either boiled in open vessels or was scoured in closed vessels under pressure and at a temperature up to 135.degree.C. The fiber material was treated for a period of time varying between a few minutes up to 5 or even 8 hours depending upon the type of the starting material and the process employed.
Usually suitable auxiliary agents or adjuvants such as alkali metal polyphosphates and/or wetting agents were added to such alkaline baths.
German Auslegeschrift No. 1,273,481 discloses a process of bleaching fiber material of native cellulose in the absence of oxidizing agents in which 4% to 13%, by weight, of sodium hydroxide and 1% to 4%, by weight, of alkali metal polyphosphates and/or amino polycarboxylic acids such as N-hydroxy ethylene diamino triacetic acid, o-cyclohexylene diamino tetraacetic acid, nitrilo triacetic acid, and ethylene diamino tetraacetic acid were added to the bleaching bath. However, these known methods of pretreating and finishing fiber material composed of native cellulose have many disadvantages. The most important disadvantage of these methods is that they affect and damage the fiber.